Shattered glass after a bomb went off at the Trader's Hotel in Yangon, Burma. Photograph: Soe Than Win/AFP/Getty

A homemade timebomb went off in a prestigious Rangoon hotel on Monday, ripping apart a room and injuring an American guest, Burmese authorities have said. It was part of a wave of unexplained blasts in recent days.

The police officer Myint Htwe said three suspects had been detained in relation to the blast, which occurred just before midnight at the Traders hotel.

The hotel bombing was followed by two small explosions before dawn on Tuesday in the Mandalay region, police said, adding that there were no reports of injuries.

The blast at the 22-storey Traders hotel, located in the heart of the country's commercial capital, blew out a window in the guest's ninth floor room, shooting shards of thick glass more than 30 metres into the street. There was no other visible damage to the exterior of the building. The device apparently went off in the guest's bathroom.

A 43-year-old American woman was slightly injured and taken to hospital, police and hotel staff said. Her husband and their two children, aged five and seven, were unhurt.

"Our consular officers in Rangoon have visited the US citizen and are providing appropriate consular assistance," said Sarah Hutchison, the US embassy spokeswoman.

Unidentified assailants have planted several homemade bombs in and around Rangoon in recent days, reportedly killing two people and injuring three others.

The first bomb reportedly went off on Friday at a guesthouse in Taungoo, a town 125 miles (200km) from Rangoon, according to independent media outlet the Democratic Voice of Burma. It said two people were killed but those casualties could not immediately be confirmed.

On Sunday two other homemade bombs went off in Rangoon. One, attached to the bottom of a truck parked outside a market on Rangoon's eastern side, wounded three civilians, according to a statement by Burmese police.

Another homemade bomb exploded at a bus stop in the west of the city but no casualties were reported in that blast, police said.

The explosions on Tuesday took place at 3am and 5am in Sagain in Mandalay region. No further details were available. No one has claimed responsibility for any of the incidents.

Traders' general manager, Phillip Couvaras, said in a statement that the hotel, part of the Shangri-La group, was working with authorities to investigate what happened.

Small explosions occurred frequently when Burma was under 50 years of military rule. They were mostly blamed on anti-government student activists or armed ethnic insurgent groups. But such incidents have become rare in recent years.